Angularfire2-如何反转可观察列表

Question

I'm using this code to reverse the list:

this.items = this.db.list('/privacy').map( (array) => {return array.reverse()} ) as FirebaseListObservable<any[]>;

and l called the list in this way:

<ion-item *ngFor="let item of items | async"> {{item.order}}</ion-item>

and this work for me (the array was reversed). but my problem not here, my problem is when a new data pushed to the list the order of the list messed up!. After refreshing the page the order reverse again.

this is a chat application not professional way to reload the page or restart the app.

Answer 1

Try this:

this.db.list('/privacy',{
  query: {
    orderByChild: 'createDate' //replace with the field you want to order by
  }
  })
  .subscribe((items: any[]) =>{
    return items.reverse();
  })

Answer 2

This works when working with an observable array

<div *ngFor="let item of (items | async).?reverse()">

Not sure if this applies to AngularFireLists